Buses will replace trains south of Perth this weekend.
ScotRail and LNER passengers are being warned about engineering works taking place on the line between Perth and Stirling.
It means anyone heading from Tayside to the Glasgow area will have to use the replacement buses for part or all of their journey.
Services travelling between Inverness and Edinburgh will also be diverted through Fife, meaning longer travel times.
ScotRail services on Saturday
Glasgow Queen Street-Perth/Dundee/Arbroath services: Train services will operate between Glasgow and Stirling and between Perth and Dundee/Arbroath. Buses will replace trains between Stirling and Perth, calling at Bridge of Allan, Dunblane and Gleneagles.
Edinburgh-Inverness services: Train services will divert via Fife and will not call Stirling. Buses will replace trains between Stirling and Perth.
Glasgow Queen Street-Inverness/Elgin services: Buses will replace trains between Glasgow Queen Street and Perth.
Glasgow Queen Street-Aberdeen services: Buses will replace trains between Glasgow Queen St and Perth.
The 11.05pm and 11.35pm Glasgow Queen Street to Perth services will be replaced by buses.
ScotRail services on Sunday
Glasgow Queen Street-Aberdeen services: Buses will replace trains between Glasgow Queen Street and Perth.
Edinburgh-Inverness services: Train services will divert via Fife and will not call Stirling. Buses will replace trains between Stirling and Perth.
Edinburgh-Dunblane/Perth services: Buses will replace trains between Stirling and Dunblane/Perth.
Glasgow Queen Street-Inverness/Elgin services: Buses will replace trains between Glasgow Queen St and Perth.
LNER services on Saturday and Sunday
Trains to and from Inverness will run via a diversionary route between Edinburgh and Perth with journey times extended by about 20 minutes.
A rail replacement coach service will be provided between Edinburgh, Falkirk Grahamston, Stirling, Gleneagles and Perth.
The buses will pick up and drop off passengers from the car park beside the entrance to Perth station.
More engineering works are planned for the following weekend.
Updates and travel advice are being provided by Network Rail.
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